Coexpression of GABA and m-erg3 in mouse embryonic spinal cord at E15. A, B, GABA immunoreactivity in sections incubated in the presence (A) or absence (B) of anti-GABA antibody (secondary antibody only). E, F, m-erg3 expression detected by NR-ISH with specific antisense (E) and sense (F) riboprobes. C, D, G, H, Detection in the same slice of m-erg3 (C, D) and GABA (G, H) in the ventral (C, G) and dorsal (D, H) region of the E15 spinal cord. Note that most of m-erg3-expressing cells are GABA-positive cells (m-erg3-positive, GABA-negative cells are indicated with arrows). Scale bars: A, B, E, F, 200 μm; C, D, G, H, 18 μm.